EP0490809A1 - Method and extrusion die for making ski running soles - Google Patents

Abstract

For making a ski running sole, a strip of plastic (14) is formed in a slot die (10) by extrusion. The plastics material to be extruded is in this case delivered in a main strand (11) and in secondary channels (12, 16), so that the strip is provided on at least one flat side with webs (15, 15a) of a second plastics material. <IMAGE>

Description

The invention relates to a method and an extrusion die for producing a ski base made of plastic.

Ski coverings made of plastic are made in a variety of ways. So-called peeling processes are known, for example, in which a sintered plastic blank is cut open with a peeling knife, a plastic band being formed, which is then cut to length and processed into ski coverings.

In such processes, multilayer coverings can be produced relatively easily by producing the sinter block from a mixture of different plastics (e.g. in layers).

It is also already known to produce ski coverings using the extrusion process. This creates an endless plastic band, in which a surface suitable for bonding, in particular gluing to the ski is then usually produced on one side by surface treatment (e.g. grinding).

In view of the very small thickness of ski coverings, only those processes for producing a multi-layer ski base in extrusion technology have become known in which various plastics were extruded over one another in the full slot width in order to obtain a quasi-sandwich structure. The invention aims to produce coverings from different materials in which, for example, the tread also has different materials.

According to the invention, this object is achieved primarily according to the characteristics of the independent claims. The co-extrusion of a ski base is made possible in an optimally simple manner in that the second extrudate is fed to the main extrusion strand in individual tracks and / or intermittently. The result of this is that a multi-layer covering is produced which has a multiplicity of webs which are fed to the main extrusion strand.

The method according to the invention can be implemented particularly easily if the main extrusion strand, in which a first plastic extrudate is fed to a slot die, is supplied with a second extrudate in individual webs and / or intermittently from at least one flat side of the slot die, and when the blended Plastic strands are extruded as a tape through the slot nozzle.

In this way, plastic sheets can be produced which contain co-extruded sheets of a second or a third plastic in the longitudinal and / or transverse direction of the sheet or the ski base made therefrom. Appropriate material and / or color combinations can be used to influence the properties of the ski base as well as to create color-attractive coverings.

It is particularly advantageous if the tape produced in this way is processed, in particular ground, on the surface side on which the second extrudate has been fed in, with a pretreatment for gluing to the ski. For example, a transparent plastic can then be extruded in the main extrusion strand, to which the second plastic is fed in from one side in individual tracks. On the side on which the various plastics are arranged next to one another, sanding and gluing is carried out, while on the opposite side a homogeneous surface is formed from the plastic of the main strand. The shimmers second plastic, if it has a different color, through the transparent plastic of the main strand.

Of course, the opposite way can also be followed, i.e. that in order to influence the running properties in a targeted manner by using two or more plastics, these are fed to the main extrusion line in webs and / or intermittently on the running side.

Even when secondary strands are fed from both sides, the running and strength properties of the covering as well as the visual impression can be influenced in a simple manner.

• Fig. 1 die schematische Ansicht eines Extruders mit Schlitzdüse zur Durchführung des erfindungsgemässen Verfahrens,
• Fig. 2 einen Schnitt durch die Schlitzdüse gemäss Linie I-I in Figur 1,
• Fig. 3 einen Schnitt längs der Linie II-II in Figur 2,
• Fig. 4 die schematische Darstellung einer abgewandelten Ausführungsform einer Schlitzdüse mit den Merkmalen der Erfindung,
• Fig. 5 einen Schnitt längs der Linie III-III in Figur 4,
• Fig. 6 einen Ausschnitt in vergrössertem Massstab aus einem Schnitt durch eine extrudierte Bahn längs der Linie IV-IV in Figur 2,
• Fig. 7 die Bahn gemäss Figur 6 nach der Oberflächenbearbeitung,
• Fig. 8 die vergrösserte, ausschnittsweise Darstellung eines Schnitts durch eine extrudierte Bahn längs der Linie V-V in Figur 4,
• Fig. 9 die Darstellung eines Schnitts längs der Linie VI-VI in Figur 8,
• Fig.10 eine Draufsicht auf die Bahn gemäss Figur 9 mit einem Teilschnitt längs der Linie VII-VII in verkleinertem Massstab,
• Fig.11 eine Draufsicht auf einen Skibelag in abgewandelter Form,
• Fig.12 eine Schlitzdüse mit beweglichen Nebenkanälen, und
• Fig.13 einem mit der Schlitzdüse gemäss Fig. 12 hergestellten Belag im Schnitt.

The invention is explained below in exemplary embodiments with reference to the drawings. Show it:

• 1 shows the schematic view of an extruder with a slot die for carrying out the method according to the invention,
• 2 shows a section through the slot nozzle according to line II in FIG. 1,
• 3 shows a section along the line II-II in FIG. 2,
• 4 shows the schematic representation of a modified embodiment of a slot nozzle with the features of the invention,
• 5 shows a section along the line III-III in FIG. 4,
• 6 shows a section on an enlarged scale from a section through an extruded web along the line IV-IV in FIG. 2,
• 7 shows the web according to FIG. 6 after surface processing,
• 8 shows the enlarged, partial representation of a section through an extruded web along the line VV in FIG. 4,
• 9 shows the representation of a section along the line VI-VI in FIG. 8,
• 10 shows a plan view of the web according to FIG. 9 with a partial section along the line VII-VII on a reduced scale,
• 11 shows a plan view of a ski base in a modified form,
• 12 shows a slot nozzle with movable secondary channels, and
• Fig. 13 a covering produced with the slot nozzle according to Fig. 12 in section.

According to FIG. 1, a schematically illustrated extruder 1 is provided in a known manner with two extrusion screws 2 and 3, each of which is driven by a drive motor 4 or 5. Plastic granules 6, 7 are fed to each of the extrusion screws 2, 3 from a hopper 8 and 9, respectively. The extrusion screws 2 and 3 are arranged in a known manner in a channel which is heated by a heating device (not shown) in such a way that the plastic granules 6, 7 melt when conveyed by the extrusion screws 2, 3 and are fed to a slot nozzle 10 in the plastic, deformable state becomes. The extrusion screw 2 supplies the plastic material for the main strand 11 (FIGS. 1 to 5) in the slot nozzle 10, while the extrusion screw 3 supplies plastic material to a large number of secondary channels 12 (Figures 2 and 3). In the course of the operation, a continuously extruded plastic band 14 is thereby produced in the slot nozzle 10, the underside of which consisted continuously of the material produced by the extrusion screw 2 and the top of which was provided with a large number of individual webs 15 of the material supplied by the extrusion screw 3. The shape of the webs 15, the thickness of the band 14 and the relative material content of the plastic granules 6 and 7 can be determined depending on the application. According to FIG. 6, the webs 15 run on the upper side of the belt 14, the material conveyed by the extrusion screw 2 being transparent, while the plastic material supplied by the extrusion screw 3 is colored. Accordingly, the webs 15 shimmer through the band 14.

FIG. 6 shows the strip after the extrusion, while FIG. 7 shows the strip 14 after an aftertreatment (grinding) in which the thickness a has been ground off the surface of the strip 14. This grinding process makes the surface absolutely flat and also gives it a roughness that enables it to be glued to the underside of a ski.

From FIG. 2 (section along the line I-I in FIG. 1) it is particularly easy to see how the individual webs 15 are produced on the belt 14 through the secondary channels 12.

Figure 3 shows a schematic section along the line II-II in Figure 2. It can be seen how the secondary channels 12 are fed from a flat side in the slot nozzle 10 to the main line 11.

In the modified exemplary embodiment according to FIGS. 4 and 5, a main line 11 and a plurality of secondary channels 12 are provided in the slot nozzle 10 analogously to FIGS. 1 to 3. In addition, there is another secondary strand 16 in the slot nozzle 10 arranged so that it opens into the main line 11 from below. The plastic material is continuously mixed in the secondary ducts 12, but intermittently in the secondary branch 16 in the main branch 11. In this way, according to FIGS. 8 and 9, a band 14 results, in which, analogously to FIGS. 5 and 7, webs 15 running in the longitudinal direction are formed on the upper side, but transverse webs 15a are formed on the underside. As can be seen from FIG. 10, due to the transparency of the plastic material of the main strand 11, the pattern of the intersecting webs 15 and 15a (colored) is translucent.

FIG. 11 shows the exemplary embodiment of a band 14 which is produced with a slot nozzle according to FIGS. 1 to 3. However, the webs 15 made of the second plastic material are interrupted because the supply of the plastic material from the extrusion screw 3 was designed intermittently (similar to FIG. 10).

FIG. 12 shows the schematic sectional illustration of an extrusion nozzle 10, in which tubular secondary channels 12a open into the main line 11. The secondary channels 12a are designed as tubular nozzles which are mounted in bores 10b in the slot nozzle 10 in such a way that they can be moved upwards or downwards in the direction of arrow A relative to the main line 11. This is done by a schematically represented hydraulic drive device 20, which is connected to a feed line 12b for the secondary lines 12a.

FIG. 13 shows how the webs 15 of the second plastic material are distributed in a wave shape in the band 14 by such an upward and downward movement of the secondary channels 12a. The second plastic material 15 can be fed intermittently or continuously. Of course, the secondary strands 12a can also be designed in such a way that that there is a continuous web 15 of the second plastic material in the transverse direction of the band 14, which runs continuously or intermittently in the longitudinal direction of the band 14 and thereby makes a wave movement. In this way, coverings can be produced particularly well in which the properties of the different plastic materials are used variably and according to the application.

Obviously, the arrangement according to the invention and the new method allow a multitude of admixture forms of different plastics to be produced and the physical behavior of the ski base to be modified almost without limit. Intermittent admixing of the plastic can be effected in a known manner by correspondingly controlling the drive motors, especially the drive motor 5 for the extrusion screw 3. Devices for such control tasks are known and familiar to the person skilled in the art.

Claims (7)

Method for producing a ski base made of plastic in the extrusion process, a first extrudate being fed to a slot die (10) in a main extrusion line (11) and a second extrudate being fed to the main extrusion line (11) in individual tracks (15, 15a) and / or intermittently becomes. Method according to claim 1, characterized by the following method steps: a) In a main extrusion strand (11), a first plastic extrudate is fed to a slot die (10); b) the main strand of the first extrudate is supplied with at least one flat side of the slot die (10) a second extrudate in individual tracks (15, 15a) and / or intermittently; c) the blended plastic strands are extruded through the slot nozzle (10) as a band (14); d) the band (14) is processed, in particular ground, on the surface side on which the second extrudate has been fed in, with a pretreatment for bonding with a ski. Method according to one of the preceding claims, characterized in that the second extrudate is fed in relation to the first extrudate in webs (15a) which increase and decrease in cross section. Extrusion nozzle for producing a ski base made of plastic with a main extrusion channel (11) to form a band-shaped body (14), wherein in the main extrusion channel (11) from at least one flat side of the nozzle 10 at least one secondary channel (12, 16) for web-like and / or intermittent feed of a second extrudate opens. Extrusion nozzle according to Claim 4, characterized in that a plurality of secondary channels (12) are fed to the main extrusion channel (11) from at least one flat side. Extrusion nozzle according to claim 4 or 5, characterized in that the secondary channel or channels (12a) in the main strand (11) are arranged to be displaceable or movable. Use of a co-extrusion slot die for producing a ski base with a main strand (11) for forming a first extrusion strand from a first extrudate and at least one secondary strand (12, 16) for feeding a second extrudate to the main strand (11).

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